Found in Radio Electronics from the 90s, this thermometer uses an integrated circuit that is unusual today. The sensor is a thermistor or NTC.
Circuits like this one, using the LM386 audio amplifier, are available from other sources in this...
This bass and treble control only attenuates the corresponding signals, requiring further...
Using a large inductance, this circuit was found in a Popular Electronics from the 90s. The...